Production of Extracellular Polysaccharide from Yeasts by Batch Fed-batch Fermentation

• Main Authors: Shih-Wei Huang, 黃世偉
• Other Authors: Dey-Chyi Sheu
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/73620054875789240173

碩士 === 大同大學 === 生物工程研究所 === 90 === Recently, being able to serve as a raw material for the synthesis of sulfated oligosaccharide, a potential anticoagulant, anti-virus and anti-tumor agent, yeast extracellular polysaccharide was becoming attractive. Batch and fed-batch fermentation was carried out in a 5-liter jar fermenter for the production of extracellular polysaccharide from Pichia holstii CCRC 22637. The fermentation medium consisted of the following ingredients per liter: glucose, 60; tryptone, 1; corn steep liquor, 1; KH2PO4, 10; MgSO4Ÿ7H2O, 0.2; MnSO4ŸH2O, 0.01; FeSO4Ÿ7H2O, 0.01 and NaCl, 0.01. Fermentation was carried out under the following conditions: initial working volume, 2 L; agitation, 450 rpm; aeration, 2 L min－1; temperature, 25°C and pH controlled at 4.7-5.3. After a 80-hr batch fermentation, 10.9 g L－1 dry weight of cells and 53.4 g L－1 dry weight of extracellular polysaccharide were obtained. When glucose and phosphate content in the medium was doubled, 10.6 g L－1 dry weight of cells and 73.2 g L－1 dry weight of extracellular polysaccharide was achieved at hr 124. In fed-batch fermentation, when half of initial glucose in the medium was exhausted, one tenth working volume of a solution containing 60 % (w/v) glucose and 5% (w/v) KH2PO4 was fed into fermenter and three repeated operations for such feeding were carried out throughout the fermentation process. After a 336-hr fed-batch fermentation, 12.3 g L－1 dry weight of cells and 112 g L－1 dry weight of extracellular polysaccharide were obtained. In a similar process of fed-batch fermentation, when nitrogen source was doubled in concentration, 21.6 g L－1 dry weight of cells and 129 g L－1 dry weight of extracellular polysaccharide were achieved at hr 364.